From the little documentation found on the 1653. This unit is a professional single channel
EQ. The low pass and high pass can be put in the off position. The { high pass} is adjustable form off ,20 ,40 ,80, 160 hz and { low pass } off, 5, 8 ,12.5, and 20 khz .

You need 2 1653 for 2 channels operating system.